Wikenigma - an Encyclopedia of Unknowns
Wikenigma - an Encyclopedia of the Unknown
Wikenigma - an Encyclopaedia of Unknowns
Wikenigma - an Encyclopaedia of the Unknown

Water - its origin

One obvious difference between Earth and other planets in the Solar System is that it's 70% covered in water. There are at least five major (and very different) theories proposing the origins of such a large volume of water (estimated at 1.3 billion cubic kilometres).

“The question of the origin of water on Earth, or the question of why there is clearly more water on the Earth than on the other planets of the Solar System, has not been clarified.”